Radiology

the study of the effects of ionizing radiation on living tissue

T or F. in diagnostic radiography, not all x-rays pass through the patient and reach the dental x-ray film; some are absorbed by patient tissues

the total transfer of energy from the x ray photon to the pt tissues

what happens when x-ray energy is absorbed by pt tissues?

What are 2 specific mechanisms of radiation injury?

x-rays are a form of________ radiation, when x rays strike patients tissues,_______results

what is produced throught he photoelectric effect, or compton scatter, and results in the formation of a positive atom and a dislodged negative electron?

forms a positive atom and a dislodged negative electron

Ionization caus____ ______in the cell that results in biological damage

Ionization causes chemical changes in the cell that results in ____ _______

X radiation causes cell damage primarily through formation in which type of radiation injury?

occurs when an x ray photon ionizes water

What is the primary component of living cells?

Ionization of water results in the production of_____ and____ _____ ____

an uncharged (neutral) atom or molecule that exists with a single, unpaired electron in its outermost shell

true or false. a free radical is highly reactive and unstable

What are 3 ways that free radicals can achieve stability?

What toxin s formed when a free radical combines with ordinary molecules and forms a toxin?

Damage to living tissues due to exposure to ionizing radiation may result from what 2 things?

What are the 2 theories about how radiation damages bioligic tissues?

suggests that cell damage results when ionizing radiation directly hits critical areas whtin the cell

What is an example of a critical area in the cell in the direct theory?

Do direct injuries from exposure toionizing radiation occur frequently or infrequently?

suggests the x-ray photons are absorbed within the cell and cause the formation of toxins, which in turn damage the cell

when x-ray photons are absorbed by water within a cell ___ ____ _______ results

In the indirect theory the free radicals combine to form_____ which cause cellular dysfunction and_______ _______

an indirect injury results because the _____ ______ combine and form ______

Why is the chance of free radical formation and indirect injury treat?

used to correlate the 'response' or damage, of tissues with the 'dose' or amount, of radiation recieved

When dose and damage are plotted on a graph, a______, ________ relationship is seen

indicates tat the response of the tissues is directly proportional to the dose

indicates that a threshold dose level for damage does not exist, suggests that no matter how small the amount of radiation recieved, some damage occurs

Is there a safe amount of radiation exposure?

Biologic effects from radiation can be classified as what 2 types?

______ effects occur as a direct function of dose

In what effect does the probability of occurrence increase with increasing absorbed dose; however, the severity of effects does not depend on the magnitude of the absorbed dose?

true or false. stochastic effects do not have a dose threshold

What are 2 examples of stochastic effects?

What is another name for nonstochastic effects?

somatic effects that have a threshold and increase in severity with increasing absorbed dose

What are 4 examples of nonstochastic effects?

Which biologic effect requires more radiation doses to seriously impair health?

chemical reactions (ionization, free radical formation) that follow the absorption of radiation occur rapidly at the______ _______

varying amounts of time are required for chemical reaction (ionization, free radical formation) changes to alter____ and _____ _______

true or false. the observable effects of radiation are not visible immediately after exposure

the time that elapses between exposure to ionizing radiation and the appearance of observable clinical signs

The latent period may be short or long depending on what 2 things?

The more radiation recieved, and the faster the dose rate, the_________the latent period

cell death, changes in cell function, breaking or clumping of chromosomes, formation of giant cells, cessateion of mitotic activity, or abnormal mitotic activity are all examples of what?

What is the last event in the sequence of radiation injury?

What is the order of the radiatio injury sequence?

true or false. all cellular radiation injuries are permanent

with each radiation exposure, cellulear damage is followed by____

Most of the damage caused by _______ radiation is repaired with cells of the body.

effects of radiaion exposure are additive and damage that remains unrepaired accumulates in the tissues, is termed:

____________ of repeated radiation exposure can lead to health problems.

Radiation effect on hematopoietic (blood forming):

radiation effects on reprocuctive (ova, sperm)

radiation effects on thyroid

radiation effects on skin

radiation effects on eyes

Name 5 factors that influence radiation injury:

the quantity of radiation received, or the total amount of radiation energy absorbed

the rate at which exposure to radiation occurs and absorption takes place

dose rate = _______

Why does more radiation damage take place with high dose rates?

the areoas of the body exposed to radiation

What is an example of total body irradiation?

extensive radiation injury occurs when large areas of the body are exposed because of the damage that occurs to the______ _________ _________

true or false. cell sensitivity affects radiation injury

are children or adults more susceptible to radiation damage?